4-29.  Cleaning,  Inspection  and  Repair Clean, inspect and repair vent damper and control as  follows: a. Wipe off all loose dirt with a dry cloth. b. Inspect push-pull control for smooth operation of  core  in  casing.  Inspect  vent  damper  for  bent  or broken  condition.  Replace  defective  parts.  Inspect for loose or damage rubber seal or damper. Cement loose rubber or replace rubber if damaged. Inspect actuator  for  bent  condition.  Straighten  actuator  or replace  as  required. 4-30.  Installation a. Vent Control Actuator.  Refer to figure 4-7 and install actuator, screw, two spring washers and nut. b.  Vent  Damper.  Refer  to  figure  4-8  and  install vent  damper  in  opening  in  housing.  Secure  vent dam per cover to housing with two screws and lock washers. c. Push-Pull Control. Refer to figures 4-7 and 4-8 and  install  control  as  follows: (1) With one nut on each end of outer casing of push-pull  control,  install  ends  of  control  through opening  in  housing.   Install  outer  nuts  and  insert ends  of  wire  core  into  mechanical  posts  of  damper and  actuator.  Tighten  outer  nuts  on  casing. (2)   Install   clamp,   spacer,   screw,   nut   and washer. (3)  Refer  to  paragraph  4-27  and  adjust  the control. (4)   Refer   to   paragraph   4-21   and   install housing  covers. (5)   Refer   to   paragraph   4-18   and   install evaporator  inlet  and  outlet  louvers. Section   X. ELECTRICAL   SYSTEM 4-31.  General The electrical system consists of the evaporator and condenser  fan  motors,  electric  heaters  and  heater thermostatic  switch,  junction  box,  control  module, transformer,  rectifier,  condenser  fan  motor,  high- low   speed   thermostatic   switch   and   connecting harnesses and wiring. Single phase air conditioners are  equipped  with  motor  capacitors  and  a  com- pressor-start relay. Three phase air conditioners are equipped   with   phase   sequence   relays.   Electrical assemblies  and  groups  of  associated  components are  covered  in  separate  sections. Warning: Disconnect air conditioner power supply  before  performing  maintenance  work on electrical system. 4-32.   Testing   and   Inspecting   the   Electrical System Troubleshooting   procedures   for   testing   the   elec- trical system to isolate cause of trouble are covered in  paragraph  4-12.  Additional  detailed  test  in- form   at   ion   is   contained   in   specific   paragraphs covering  the  electrical  components.  Use  a  con- tinuity tester or multimeter set on low ohms range to  test  for  continuity.  Use  an  insulation  tester  or multimeter set on high ohm range to test for shorts between the circuit in a component and the outside case  of  the  component.  When  testing  air  electrical component,   check   also   for   visual   damage   and inspect  all  wiring  in  the  area  for  damage  or  loose connections. 4-33.   Wiring   Harnesses   and   Leads a.   General.   The  electrical  circuits  in  the  air conditioner are completed by individual wire leads or by wire leads laced or enclosed in a loom to form a  wiring  harness.  All  of  the  wiring  carries  code numbers. When testing, repairing, or replacing the wiring  harness  or  individual  wires,  refer  to  the wiring  diagrams. b. Inspection.  Inspect all wiring installations for cracked   or   frayed   insulation   material.   Pay   par- ticular attention to wires passing through holes in the frame or around sharp edges. Repair or replace defective  wiring.  Inspect  electrical  connectors  and fittings  for  damage  or  broken  condition.  Replace defective  connectors  and  fittings. c. Testing.  Test for continuity in leads or wiring harnesses  by  disconnecting  each  end.  Where  wires terminate   in   an   electrical   connector,   disconnect connector  from  corresponding  receptacle  connector or  plug  connector.   Touch  the  test  probes  of  a continuity  tester  or  multimeter  set  on  low  ohms range  to  ends  of  wire  or  to  corresponding  pin  of connector.  If  continuity  is  not  indicated,  repair  or replace  wire. d. Repair.  Remove  insulation  to  expose  1/2  inch of  bare  wire  on  each  side  of  break.  Twist  the  wire ends together and solder the splice. Cover the splice with rubber or PVC electrical tape and friction tape making certain  to  cover  all  the  repaired  area. Replace broken terminal lugs with exact duplicates. To   replace   electrical   connectors.   unsolder   wires from  solder  wells  of  inserts.  Install  new  connector and  insert  ends  of  wires  in  solder  wells.  Solder  wires in  place.  Check  connections  carefully.  Refer  to wiring  diagram. 4-17